This invention relates to a membrane and electrode structure composed of an ion exchange membrane having a plurality of electrically-conductive, catalytically-active particles present on one, or both, surfaces of an ion exchange membrane. These membrane and electrode structures are particularly useful in fuel cells and electrolytic cells.
It is known to prepare membrane and electrode structures by depositing a catalyst ink comprising catalytically-active particles, a suspension medium comprising a hydrocarbon having an ether, epoxy, or ketone linkage and an alcohol group, and a binder, onto a solid polymer electrolytic material such as a polymeric membrane as described, for example, in U.S. Pat. No. 5,330,860. U.S. Pat. No. 5,234,777 describes solid polymer electrolyte membrane assemblies consisting essentially of a solid polymer electrolyte membrane and a composite film of a supported platinum catalyst and a proton-conducting ionomer with a thickness less than about 10 .mu.m and a platinum loading of less than about 0.35 mg Pt/cm.sup.2. Japanese Patent Application No. H6-260185 discloses a gas diffusion electrode prepared from a perfluorosulfonate polymer having an equivalent weight of at least 950. However, the performance of such structures in a proton exchange membrane fuel cell may be less than desirable for certain fuel cell applications.